Clinically oriented research in the elderly is of growing interest because of increasing numbers of older persons, the relative lack of research data with this population, and recent Food and Drug Administration mandates to study drugs in the elderly. Studies of young, healthy persons cannot necessarily be extrapolated to the elderly due to changes associated with aging and the increased number of concomitant disease states and medications. Subject recruitment may be more time consuming in finding subjects with the appropriate inclusion criteria and lack of exclusion criteria who are willing to participate. Additional concern must be placed on protecting the subject's rights while allowing autonomous decision making. Likewise, protocols may need to be flexible enough to include persons with concomitant disease and medications.